Coverage Summary for Class: Platform (com.google.common.base)

1 /*
2  * Copyright (C) 2009 The Guava Authors
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5  * in compliance with the License. You may obtain a copy of the License at
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software distributed under the License
10  * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11  * or implied. See the License for the specific language governing permissions and limitations under
12  * the License.
13  */
14 
15 package com.google.common.base;
16 
17 import com.google.common.annotations.GwtCompatible;
18 import java.lang.ref.WeakReference;
19 import java.util.Locale;
20 import java.util.ServiceConfigurationError;
21 import java.util.logging.Level;
22 import java.util.logging.Logger;
23 import java.util.regex.Pattern;
24 import javax.annotation.CheckForNull;
25 
26 /**
27  * Methods factored out so that they can be emulated differently in GWT.
28  *
29  * @author Jesse Wilson
30  */
31 @GwtCompatible(emulated = true)
32 @ElementTypesAreNonnullByDefault
33 final class Platform {
34   private static final Logger logger = Logger.getLogger(Platform.class.getName());
35   private static final PatternCompiler patternCompiler = loadPatternCompiler();
36 
37   private Platform() {}
38 
39   /** Calls {@link System#nanoTime()}. */
40   @SuppressWarnings("GoodTime") // reading system time without TimeSource
41   static long systemNanoTime() {
42     return System.nanoTime();
43   }
44 
45   static CharMatcher precomputeCharMatcher(CharMatcher matcher) {
46     return matcher.precomputedInternal();
47   }
48 
49   static <T extends Enum<T>> Optional<T> getEnumIfPresent(Class<T> enumClass, String value) {
50     WeakReference<? extends Enum<?>> ref = Enums.getEnumConstants(enumClass).get(value);
51     return ref == null ? Optional.<T>absent() : Optional.of(enumClass.cast(ref.get()));
52   }
53 
54   static String formatCompact4Digits(double value) {
55     return String.format(Locale.ROOT, "%.4g", value);
56   }
57 
58   static boolean stringIsNullOrEmpty(@CheckForNull String string) {
59     return string == null || string.isEmpty();
60   }
61 
62   /**
63    * Returns the string if it is not null, or an empty string otherwise.
64    *
65    * @param string the string to test and possibly return
66    * @return {@code string} if it is not null; {@code ""} otherwise
67    */
68   static String nullToEmpty(@CheckForNull String string) {
69     return (string == null) ? "" : string;
70   }
71 
72   /**
73    * Returns the string if it is not empty, or a null string otherwise.
74    *
75    * @param string the string to test and possibly return
76    * @return {@code string} if it is not empty; {@code null} otherwise
77    */
78   @CheckForNull
79   static String emptyToNull(@CheckForNull String string) {
80     return stringIsNullOrEmpty(string) ? null : string;
81   }
82 
83   static CommonPattern compilePattern(String pattern) {
84     Preconditions.checkNotNull(pattern);
85     return patternCompiler.compile(pattern);
86   }
87 
88   static boolean patternCompilerIsPcreLike() {
89     return patternCompiler.isPcreLike();
90   }
91 
92   private static PatternCompiler loadPatternCompiler() {
93     return new JdkPatternCompiler();
94   }
95 
96   private static void logPatternCompilerError(ServiceConfigurationError e) {
97     logger.log(Level.WARNING, "Error loading regex compiler, falling back to next option", e);
98   }
99 
100   private static final class JdkPatternCompiler implements PatternCompiler {
101     @Override
102     public CommonPattern compile(String pattern) {
103       return new JdkPattern(Pattern.compile(pattern));
104     }
105 
106     @Override
107     public boolean isPcreLike() {
108       return true;
109     }
110   }
111 
112   static void checkGwtRpcEnabled() {
113     String propertyName = "guava.gwt.emergency_reenable_rpc";
114 
115     if (!Boolean.parseBoolean(System.getProperty(propertyName, "false"))) {
116       throw new UnsupportedOperationException(
117           Strings.lenientFormat(
118               "We are removing GWT-RPC support for Guava types. You can temporarily reenable"
119                   + " support by setting the system property %s to true. For more about system"
120                   + " properties, see %s. For more about Guava's GWT-RPC support, see %s.",
121               propertyName,
122               "https://stackoverflow.com/q/5189914/28465",
123               "https://groups.google.com/d/msg/guava-announce/zHZTFg7YF3o/rQNnwdHeEwAJ"));
124     }
125     logger.log(
126         java.util.logging.Level.WARNING,
127         "Later in 2020, we will remove GWT-RPC support for Guava types. You are seeing this"
128             + " warning because you are sending a Guava type over GWT-RPC, which will break. You"
129             + " can identify which type by looking at the class name in the attached stack trace.",
130         new Throwable());
131   }
132 }